铜(Ⅱ)-曙红B-洛美沙星的共振瑞利散射的研究与应用

在pH 4.0的BR缓冲介质中,洛美沙星能与铜(Ⅱ)形成螯合阳离子,再通过静电引力和疏水作用,与曙红B阴离子形成缔合物,导致共振瑞利散射(RRS)显著增强。在最大RRS峰380 nm处,散射光增强值(ΔI)与洛美沙星的浓度成正比,据此建立了共振光散射法测定洛美沙星,线性范围为8.99×10-8～3.00×10-6mol/L,检出限(3Sb/k)为2.69×10-8mol/L。该法用于检测牛奶中洛美沙星的含量,并取得满意结果。该方法简单、快速、灵敏度高。     

分子印迹杂化材料的溶胶-凝胶法制备及选择性固相萃取牛奶中洛美沙星

以兽药洛美沙星为模板分子,3-氨基丙基三乙氧基硅烷为功能单体,甲基三甲氧基硅烷为交联剂,采用溶胶-凝胶分子印迹技术,以离子对及疏水作用方式,在水相体系中合成了具有分子识别作用的的新型有机-无机杂化分子印迹聚合物。静态吸附和Scatchard分析实验结果表明,此印迹材料对洛美沙星的结合存在两个结合位点,最大吸附容量分别为95.65与127.45μmol/g。以此印迹材料作为固相萃取剂,优化萃取条件,成功应用于牛奶中洛美沙星测定。     

柱切技术在环氧乙烷抑制剂在线分析中的应用

本文介绍了柱切技术在环氧乙烷多组分中抑制剂分析中的应用,及柱切技术的硬件配置,实现过程和优势。柱切技术实现了复杂组分中快速无干扰的连续分析。     

X-射线荧光仪熔片法测定石灰石中各组分

本文介绍了一种用X荧光熔片法测定石灰石中各组分的快速分析方法。用国家级石灰石标样绘制工作曲线,消除基体效应及吸收增强效应,分析速度快,操作简单,对快速冶炼起到了很好的指导作用。     

火焰原子吸收光谱法测定牛奶中铁和锌

先将牛奶碳化，再用酸溶解，利用TritonX-100使测定铁、锌的灵敏度分别提高8．3％、16．4％，且有效地消除了牛奶中存在的其他金属离子的干扰。该方法简单、快速、准确。     

多干扰样品在库仑分析中的优化

本文通过微库仑法在分析各种多干扰油品中各影响因素的对比和研究,找到了分析此类油品最佳的分析条件,成功建立了成熟的分析方法。试验结果表明:微库仑法具有快速、高效、可调性强等特点,对于分析带干扰、组分复杂的样品来说最合适。     

X射线荧光光谱法测定铁矿石中主次量组分

建立用X-射线荧光光谱法同时测定铁矿石中主次量组分(TFe、SiO2、Al2O3、MgO、CaO、Na2O、K2O、TiO2、MnO、P)的快速分析方法,在优化条件下,采用国家标准样品建立的标准工作曲线和基体校准一体回归方程进行谱线重叠干扰和基体效应校正,对国家标准物质及样品进行重复测定,分析结果与标准值吻合,相对误差RE不超过5％,相对标准偏差RSD不超过5％.该方法具有较好的准确度和精密度,能满足快速分析的需要.     

基于EEM-PARAFAC的荧光示踪剂检测方法的研究

在油田的注水开发中,利用化学示踪剂进行井间连通性测试是了解出水优势通道特征、制定提高采收率方案的必要前提。但常见的荧光示踪剂在现场应用中易受原油中荧光物质的干扰导致识别率和检测精度较低,严重影响测试结果的准确性。采用三维荧光光谱法与平行因子分析法相结合的分析方法,对在多种荧光物质干扰下的模拟采出液中的荧光示踪剂进行定性分析与定量分析,成功得出模拟采出液中荧光示踪剂浓度,经计算平均相对误差约为12.75%。该方法用三维荧光光谱的数据处理代替传统的荧光背景测试,去除模拟采出液中不同荧光物质对待检测示踪剂的干扰,具有操作简单、准确性高、成本低、检测速度快的特点,可广泛应用于复杂背景条件下荧光示踪剂的快速检测。     

水体中多环芳烃混合物的快速同步荧光光谱分析简

建立了胶束溶液中多环芳烃混合物同时测定的同步荧光分析法,该法简便快速,无需对混合物进行分离,就可实现多种组分的同时鉴别,此方法应用于分析水样中的多环芳烃取得了良好的效果。     

能量转移荧光法测定牛奶中的三聚氰胺

在pH 3.5的Britton-Robinson缓冲溶液中,酸性染料荧光素与碱性染料中性红之间能够发生有效的能量转移,在波长508nm处的荧光值与三聚氰胺的加入量有线性关系,据此建立了一种测定三聚氰胺的荧光光度法,并研究了测定三聚氰胺的最佳条件和干扰离子对体系的影响。方法的线性范围是0.4～100mg/L,检出限为0.015mg/L。将方法用于牛奶中三聚氰胺的测定,结果满意。     

洛美沙星环合物生产工艺改进研究简

洛美沙星环合物是制造盐酸洛美沙星胶囊和盐酸洛美沙星滴眼液等杀菌消炎药的医药中间体.本文是在车间工艺生产基础上,从化学检测着手,运用现代化学实验技术,分析车间工艺生产,找出洛美沙星环合物生产过程中含量不能达到医药生产的优级纯（99％以上）原因,并改进之,指导洛美沙星环合物生产工艺的改进,实现其顺利生产.     

Innovative in situ investigations using synchrotron-based micro tomography and molecular dynamics simulation for fouling assessment in ceramic membranes for dairy and food industry

Proteins in dairy streams result in organic fouling and function loss for ceramic membrane's porous structure. Synchrotron-based X-ray microtomography (SR-µCT) is a new method with a high signal to noise ratio and accordingly significant level of accuracy. The goal of this study was to perform an in situ assessment of ceramic membrane fouling in the dairy stream filtration process, using SR-µCT. This study attempted to assess porosity variation and membrane fouling through different layers from the top, middle, and bottom layers of the ceramic microfiltration membrane before and after skimming milk filtration. Molecular dynamics simulation (MDS) was used for depth understanding of milk protein interactions with the ceramic membrane. Fouling was found to be more intense on the top of the ceramic membrane even though the top layer was slightly more porous, which indicates that top layers were more prone to fouling. A regression model was derived to correlate the porosity loss due to membrane fouling at different membrane thicknesses. The MDS results showed more affinity of the milk proteins to the ceramic membrane compared to water molecules. The MDS studies showed how the presence of the milk's protein macromolecules could change the hydrophilicity trend on the membrane's surface.     

A GREENER SYNTHESIS TECHNOLOGY FOR LOMEFLOXACIN HYDROCHLORIDE

Lomefloxacin ethyl ester was prepared from 2,3,4-trifluoroaniline in ionic liquid in a one-pot procedure by condensation with EMME (ethoxymethylenemalonic diethyl ester), cyclization, ethylation, and condensation with 2-methyl piperazine. After its hydrolysis and salifying with hydrochloric acid, lomefloxacin hydrochloride was obtained with an overall yield of 58.4%. Compared with current lomefloxacin hydrochloride synthesis technology, this approach simplified its synthesis procedures, shortened its synthesis time, and eliminated the usage of volatile organic solvents.     

Effects of minor lipids on crystallization of milk fat-cocoa butter blends and bloom formation in chocolate

Minor lipids, such as diacylglycerols, monoacylglycerols, cholesterol, and phospholipids play a key role in crystallization of fats. In this study, the effects of minor lipid components on crystallization of blends of cocoa butter (CB) with 10% milk fat or milk-fat fractions, and on bloom formation of chocolate were investigated. Both removing the minor lipids from milk fat and doubling the level of minor lipids from milk fat resulted in longer nucleation onset time, slower crystallization rate, and rapid bloom development in chocolate. Removal of minor lipids resulted in the formation of irregular primary and secondary crystals with inclusions of liquid fat, whereas the crystals were spherical and uniform in shape in the presence of minor lipids. Minor lipids from milk fat, even at the low concentrations typically found in nature, affected the crystallization of milk fat-CB blends, impacted the chocolate microstructure, and affected bloom development in chocolate.     

UVA Radiation Enhances Lomefloxacin-Mediated Cytotoxic,Growth-Inhibitory and Pro-Apoptotic Effect in Human Melanoma Cells through Excessive Reactive Oxygen Species Generation

Melanoma, the most dangerous type of cutaneous neoplasia, contributes to about 75% of all skin cancer-related deaths. Thus, searching for new melanoma treatment options is an important field of study. The current study was designed to assess whether the condition of mild and low-dose UVA radiation augments the lomefloxacin-mediated cytotoxic, growth-inhibitory and pro-apoptotic effect of the drug in melanoma cancer cells through excessive oxidative stress generation. C32 amelanotic and COLO829 melanotic (BRAF-mutant) melanoma cell lines were used as an experimental model system. The combined exposure of cells to both lomefloxacin and UVA irradiation caused higher alterations of redox signalling pathways, as shown by intracellular reactive oxygen species overproduction and endogenous glutathione depletion when compared to non-irradiated but lomefloxacin-treated melanoma cells. The obtained results also showed that lomefloxacin decreased both C32 and COLO829 cells’ viability in a concentration-dependent manner. This effect significantly intensified when melanoma cells were exposed to UVA irradiation and the drug. For melanoma cells exposed to lomefloxacin or lomefloxacin co-treatment with UVA irradiation, the concentrations of the drug that decreased the cells’ viability by 50% (EC₅₀) were found to be 0.97, 0.17, 1.01, 0.18 mM, respectively. Moreover, we found that the redox imbalance, mitochondrial membrane potential breakdown, induction of DNA fragmentation, and changes in the melanoma cells’ cell cycle distribution (including G₂/M, S as well as Sub-G₁-phase blockade) were lomefloxacin in a dose-dependent manner and were significantly augmented by UVA radiation. This is the first experimental work that assesses the impact of excessive reactive oxygen species generation upon UVA radiation exposure on lomefloxacin-mediated cytotoxic, growth-inhibitory and pro-apoptotic effects towards human melanoma cells, indicating the possibility of the usage of this drug in the photochemotherapy of malignant melanoma as an innovative medical treatment option which could improve the effectiveness of therapy. The obtained results also revealed that the redox imbalance intensification mediated by the phototoxic potential of fluoroquinolones may be considered as a more efficient treatment model of malignant melanoma and may constitute the basis for the development of new compounds with a high ability to excessive oxidative stress generation upon UVA radiation in cancer cells.     

Mineral nutrient content in cow milk and dairy products in Argentina

Cow milk and dairy products supply essential inorganic elements for humans, and constitute the most important source of bioavailable calcium in our diet. In order to obtain data about mineral nutrient composition of dairy products that are produced and sold in Argentina, the contents of Ca, P, Mg, Na, K, Fe, Zn and Cu in whole and low fat fluid milk, dried milk and yogurt were analyzed. P was assessed by a colorimetric method, and the other elements by atomic absorption spectroscopy. In raw milk, the mineral content shows a certain degree of variability, in addition to the variability introduced by the different processing conditions, in order to meet the requirements prescribed by trade regulations and to produce dairy products. In all cases, skimming increases the concentration of mineral nutrients, which is especially remarkable in Ca contained in skimmed milk powder. In yogurt, added milk solids like dried milk or evaporated milk appreciably increase the mineral content, even more so if ultrafiltrates are used. These ultrafiltrates increase the Ca/P ratio, which probably improves Ca bioavailability. The results obtained in these analyses provide data that are not yet available from the National Table of Food Composition, and which prove necessary and fundamental for nutritional and dietary evaluation.     

洛美沙星滴耳液治疗急性化脓性中耳炎的临床治疗观察

目的探讨洛美沙星滴耳液治疗急性化脓性中耳炎的临床治疗效果。方法回顾性分析我院自2007年12月至2010年6月收治的196例急性化脓性中耳炎患者,随机分为2组,治疗组98例,采用洛美沙星滴耳液治疗,对照组98例,采用氧氟沙星滴耳剂治疗,比较2组治疗效果。结果治疗组总有效率91.8%;对照组总有效率82.7%,治疗组总有效率明显大于对照组,有显著的统计学差异性(P<0.05);2组在局部用药过程中有38例(治疗组17例,对照组21例)发生耳刺痛、耳痒症状,全身用药有23例出现皮肤瘙痒、头晕、恶心、呕吐等症状,减少药物剂量后症状消失,所有患者均完成治疗,无一例出现严重不良反应和并发症。纯音测定显示,用药后无一例听力较用药前下降。结论洛美沙星滴耳剂可直接作用于病变部位,抗菌活性强,作用持久,具有高效、稳定、副作用小、安全等优点,是治疗急性化脓性中耳炎的有效药物,值得在临床中推广应用。     

Molecular and Biochemical Basis of Fluoroquinolones-Induced Phototoxicity—The Study of Antioxidant System in Human Melanocytes Exposed to UV-A Radiation

Phototoxicity of fluoroquinolones is connected with oxidative stress induction. Lomefloxacin (8-halogenated derivative) is considered the most phototoxic fluoroquinolone and moxifloxacin (8-methoxy derivative) the least. Melanin pigment may protect cells from oxidative damage. On the other hand, fluoroquinolone–melanin binding may lead to accumulation of drugs and increase their toxicity to skin. The study aimed to examine the antioxidant defense system status in normal melanocytes treated with lomefloxacin and moxifloxacin and exposed to UV-A radiation. The obtained results demonstrated that UV-A radiation enhanced only the lomefloxacin-induced cytotoxic effect in tested cells. It was found that fluoroquinolones alone and with UV-A radiation decreased superoxide dismutase (SOD) activity and SOD1 expression. UV-A radiation enhanced the impact of moxifloxacin on hydrogen peroxide-scavenging enzymes. In turn, lomefloxacin alone increased the activity and the expression of catalase (CAT) and glutathione peroxidase (GPx), whereas UV-A radiation significantly modified the effects of drugs on these enzymes. Taken together, both analyzed fluoroquinolones induced oxidative stress in melanocytes, however, the molecular and biochemical studies indicated the miscellaneous mechanisms for the tested drugs. The variability in phototoxic potential between lomefloxacin and moxifloxacin may result from different effects on the antioxidant enzymes.     

Determination of milk fat in chocolates by gas-liquid chromatography of triglycerides and fatty acids

The combination of two routine methods is proposed to determine the content of milk fat (MF) in chocolates, which is applicable even in the presence of lauric fats or others. The content of MF is obtained from the sum of C₄₀, C₄₂, and C₄₄ medium-chain triglycerides, determined by capillary gas-liquid chromatography (GLC). A new method, based on methyl esters of lauric acid and on minor acids situated between myristic and palmitic, is proposed. It enables detection and estimation of potential lauric fats, as well as the determination of the actual content of MF. The influence of other vegetable and animal fats is discussed. We analyzed 45 MF samples extracted from industrial milk powders and from pure or fractionated MF for chocolate manufacturing or pastry by GLC of triglycerides. We also analyzed by capillary GLC the methyl esters from 22 of those fats. Mixtures of these 22 MF samples with a cocoa butter also were used for chromatographic analyses of methyl esters and triglyceride. Results from the various analytical methods have been presented.